This invention relates generally to methods and apparatus for joining or splicing tubing, and specifically to methods and apparatus to simultaneously engage a plurality of tubing ends.
There are many situations and applications that require splicing or connecting tubing to other tubing, or to other devices or the like. Prior art approaches include using a sleeve around a central nipple or tubular member, with the tubing end disposed and gripped between the sleeve and nipple. Force or friction is applied to cause detents or teeth on the respective sleeve and nipple pieces to bite into the tubing and hold it in the desired location. Many applications require that this be accomplished with a sufficiently tight seal to prevent leakage.
Among the various approaches in the prior art, some apply force to the detents or teeth via threads acting between the central member and the sleeve, so that rotating those pieces with respect to each other forces the teeth or detents to move axially toward each other and “bite” into the tubing end. FIG. 1a illustrates this prior art concept. Sleeve B and central member C can be rotated with respect to each other so that they are moved axially with respect to each other. Rotation in the proper direction moves the sleeve B to the left relative to member C and engages tubing D between teeth or detents E and F.
For applications in which two pieces of tubing are to be joined to each other, prior art approaches such as just described require that a mirror image of the apparatus be provided or formed on the other end of the central member. Not only is more material required (in order to provide the additional length of the central member, as well as the two separate mating sets of threads—one mating set at each end of the central member), but the assembly of the two ends to the splicing apparatus requires two separate rotations of threaded elements—one rotation or tightening/biting for each tubing end.